STAPH STRAIN FOUND TO RESIST ANTIBIOTICS.

Byline: Daily News Staff and Wire Services

A common bacterium that is the leading cause of hospital-related infections appears to be on the brink of becoming an unstoppable germ.

Scientists with the U.S. Centers for Disease Control and Prevention have confirmed that Staphylococcus aureus, better known as a staph infection, has for the first time defended itself from the last remaining drug capable of killing all its strains. The possibility of a widespread, untreatable infection has not been known since penicillin became widely used in the 1940s.

``We have a situation which is very worrisome,'' said Fred Tenover, a microbiologist who is laboratory chief of the CDC's hospital infections branch. He said the newly isolated strain demonstrated an ``intermediate'' level of resistance to the last-line antibiotic, higher than any level previously known for staph.

``If we're climbing the ladder,'' he said, ``we're almost to the roof.''

In Los Angeles County, there have been no reports of the new, potent strain of staph. But local health officials said they are on alert for any signs of the latest, formidable germ.

``We will get more interested in surveillance, asking hospitals to submit (information on) their resistant organisms so we can track as nearly as we can when it (the new germ) becomes a problem in this community,'' said Dr. Shirley Fannin, director of communicable disease control for the Los Angeles County Department of Health Services.

Staphylococcus aureus, unlike other bacteria that doctors fear might become unconquerable, often lives peacefully with the human body. But it can become a danger when it slips through an open wound or sore. It is famous for causing not only hospital infections but boils and even pimples. Before the advent of antibiotics, a large enough boil, for instance, could be fatal.

The newly discovered strain came from a Japanese infant who developed the infection after heart surgery, Tenover said. The boy eventually recovered with the aid of other drugs, but not before doctors discovered that a staph-infected abscess seemed to have some ability to resist the drug vancomycin. The Japanese doctors sent samples of the bacterium to Tenover for examination.

Vancomycin, a powerful antibiotic, is considered the last line of defense for some unusually stubborn strains of staph and other bacteria. The drug has been used for 30 years, and some doctors had hoped that perhaps staph was not capable of building a tolerance to it, said Dr. Robert Haley of the University of Texas Southwestern Medical Center at Dallas.

The fact that a patient was infected with even a moderately resistant strain ``means that we can throw out the window the hope that Staph aureus was not going to break through'' medical defenses, said Haley, former chief of the CDC's hospital infections branch.

``I can't emphasize enough, this is a major turn for the worse in the fight against infection,'' he said.

Penicillin, discovered in the 1920s, came to fame after it successfully controlled staph in the 1940s. But even the drug's discoverer, Alexander Fleming, warned that resistance would surface after its widespread use. In fact, by the 1950s, almost half of all Staph aureus strains isolated had become resistant to penicillin.

Dr. Peter Miao, an infectious diseases specialist at Sherman Oaks Hospital and Health Center, said he first began seeing tougher bacteria immune to modern antibiotics about 20 years ago.

Then in the 1960s, scientists developed a new antibiotic called methicillin. But by the late 1970s, methicillin-resistant staph had become a growing problem.

Ironically, patients partial to antibiotics partly are to blame for the growing strength of bacteria including the new staph strain. ``A lot of the time, the reason for these bacteria emerging is because we overuse, misuse antibiotics,'' Miao said. ``They (bacteria) become resistant to these powerful antibiotics.''

``Patients come into the office with a cold and they really expect to get an antibiotic prescription. If you don't give it to them, they're dissatisfied,'' Miao said. ``It's a Catch-22.''

Doctors were comforted, however, by the fact that vancomycin was still there, still working.

``Vancomycin has been a silver bullet for staph,'' Haley said.

But with the discovery of the new staph strain, vancomycin has lost some of its punch.

The CDC is drafting new guidelines to control the emergence of a possible vancomycin-resistant strain, Tenover said. The guidelines are scheduled to be published this summer in the CDC's Morbidity and Mortality Weekly Report. In addition, a discussion of the Japanese patient is expected to appear in the July issue of the Journal of Antimicrobial Chemotherapy.

Although the Japan incident represents the first identified strain of intermediate-resistant staph, other such strains may be out there, said Stuart Levy of Tufts University in Boston, who is an expert on antibiotic resistance.

``I would doubt that it's the only case,'' he said. ``It's a signal, it's an alert to hospitals all over the world to look for these organisms.''

He said the discovery of this strain could have some benefit if the finding warns medical workers to take care to control its spread.

Tenover said he is concerned that staph might follow the path of another hospital infection, vancomycin-resistant enterococcus, which also took years to develop vancomycin resistance. In a short time, it became a worldwide nuisance even though enterococcus had not previously been considered a serious menace.

``Once it showed up, it spread like fire in a lot of U.S. hospitals,'' Tenover said.

Given that history, scientists and public health experts should develop a plan for the diligent infection control, said Dr. Michael Edmond of the Medical College of Virginia.